Changes between Version 102 and Version 103 of MD_WSdiffim_photcheck_test20121004

Timestamp:

Feb 26, 2013, 1:07:51 PM (13 years ago)

Author:

Mark Huber

Comment:

--

MD_WSdiffim_photcheck_test20121004

@@ -18 +18 @@
 Two key problems were identified:
  * background binning for photometry on diffims has not been the same as other photometry (~0.1-0.2 offset mag) -- using 128 for now, may need additional/proper tuning
- * coordinate list for determining PSF was a matched+merged list of both the input and reference image rather than just a matched list (0.3+ irregular mag). When the list is sorted by inst_flux and the top hardcoded 500 sources are used, ones that are not in the input warp from masking etc reduce the available "good" sources. Normally that is only a small fraction, but when a deeper refstack is used the missing sources have a much higher inst_flux and begin to dominate the set for determining the PSF making for a poor solution. 
+ * coordinate list for determining PSF was a matched+merged list of both the input and reference image rather than just a matched list (0.3+ irregular mag). When the list is sorted by inst_flux and the top hardcoded 500 sources are used, ones that are not in the input warp from masking etc reduce the available "good" sources. Normally that is only a small fraction, but when a deeper refstack is used the missing sources have a much higher inst_flux and begin to dominate the set for determining the PSF making for a poor solution. Newer MD refstacks have been much deeper, some fields before (typically y-band) had only order 10-20 inputs, and now have 60-100.
 
 Various other minor issues identified: